• Power Monitor Light: Red For Heating and Green When Aquarium Has Reached Set Temperature • Fully Submersible and Can Be Placed Horizontally Or Vertically In The Aquarium • For Freshwater and Marine Aquariums • Shatterproof and Nearly Indestructable With Durable Aluminum Core and No Glass Components • Automatically Turns Off If Heater Is Left Out Of Water, Resets and Works Normally When Placed Back In The Water • Large Temperature Control Knob Makes Modifying The Temperature Easy